Co-sputtered Zn1-xMgxO films and interfacial band offsets at heterojunctions with SnS-CUB

Abstract Zinc magnesium oxide, Zn 1− x Mg x O, is a desirable candidate for a buffer/window layer in thin film solar cells. We deposited Zn 1− x Mg x O film with hexagonal structure by co-sputtering of ZnO and Mg targets. Band gap of the Zn 1− x Mg x O films was found to increase from 3.48 to 3.83 eV with the increase in Mg content in the film. We used X-ray photo-electron spectroscopy (XPS) to examine the interfaces formed between such Zn 1− x Mg x O films and the recently reported cubic structured SnS (SnS-CUB) thin films of bandgap 1.72 eV. The valence band maxima of the materials determined from XPS show that the conduction band offset (CBO) for Zn 0.88 Mg 0.12 O/SnS-CUB interface is 0.39 eV. The CBO, 0.52 eV of Zn 0.88 Mg 0.12 O/SnS-CUB hetero junction was also calculated from electron affinities of Zn 0.88 Mg 0.12 O and SnS-CUB thin films which is in agreement with the CBO calculated from the XPS measurements.